Electrochemical fuel cells can be used in a vast array of applications as a power source, including as an alternate power source to the internal combustion engine for vehicular applications. An electrochemical fuel cell contains a membrane sandwiched between electrodes. One preferred fuel cell is known as a proton exchange membrane (PEM), where hydrogen (H2) is used as a fuel source or reducing agent at an anode electrode and oxygen (O2) is provided as the oxidizing agent at a cathode electrode, either in pure gaseous form or combined with nitrogen and other inert diluents present in air. During operation of the fuel cell, electricity is garnered by electrically conductive elements proximate to the electrodes via the electrical potential generated during the reduction-oxidation reaction occurring within the fuel cell.
Fluid handling devices within the fuel cell circulate the process fluids (e.g. reactant gases, coolant, effluent streams) throughout the system. Fluid handling devices that deliver hydrogen-containing gases to and from the anode pose particular design challenges due to the reactivity of hydrogen and hydrogen-containing gases. The fluid handling device should sufficiently isolate the hydrogen-containing process fluids, so that the hydrogen-containing gases are not released into the surrounding environment. Fluid handling devices, such as pumps, blowers, and compressors, typically have rotating shafts that extend through the housing of a motor compartment to a process fluid compartment. The seals surrounding the shaft and separating the motor and process fluid compartments may fully seal process fluids from the environment. Other fluid handling device configurations may isolate the device from the surrounding environment by encasing it in a sealed (e.g. hermetically) protective housing. The present invention relates to improving the fluid barriers of fluid handling devices that handle reactive, corrosive, and/or combustible process fluids, which must be isolated, such as the anode process fluids handled in a fuel cell system.